Dual air conditioner for vehicle

ABSTRACT

The present invention relates to a dual air conditioner for a vehicle, which includes a rear high-temperature pipe that is connected to a rear expansion valve of a rear air conditioner and installed in such a way as to be directly branched from a dual pipe type internal heat exchanger of a front air conditioner, thereby reducing the number of required components and simplifying the manufacturing process with no need to use a connector for branching the rear high-temperature pipe from the front air conditioner, and enhancing a refrigerant movement and reducing material expenses and working process by simplifying piping work and a piping route.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dual air conditioner for a vehicle,and more particularly, to a dual air conditioner for a vehicle, whichincludes a rear high-temperature pipe that is connected to a rearexpansion valve of a rear air conditioner and installed in such a way asto be directly branched from expanded pipe parts of a dual pipe typeinternal heat exchanger of a front air conditioner.

2. Background Art

In general, an air conditioner for a vehicle is a car part, which isinstalled in a vehicle for the purpose of cooling or heating theinterior of the vehicle in the summer season or the winter season orremoving frost from a windshield in the rainy season or the winterseason to thereby secure a driver's front and rear visual fields. Suchan air conditioner typically includes a heating device and a coolingdevice together, so that it can heat, cool or ventilate the interior ofthe vehicle through the steps of selectively introducing the inside airor the outside air into the air conditioner, heating or cooling theintroduced air, and blowing the heated or cooled air into the vehicle.

In case of small cars having a narrow interior space, a single airconditioner that has one evaporator mounted in an engine room of thefront side of the car is generally applied to the small car. However, incase of some of luxury cars or RVs (Recreational Vehicles), in order tosufficiently supply an air-conditioning environment to the rear insideroom of the car, as shown in FIG. 1, a dual air conditioner thatincludes a front air conditioner 10 mounted in the engine room andhaving a front evaporator 14 and a rear air conditioner 20 mounted inthe rear side of the car and having a rear evaporator 22 is applied tothe car.

The dual air conditioner including the front air conditioner 10 and therear air conditioner 20 can simultaneously or separately operate thefront evaporator 14 and the rear evaporator 22, and the front evaporator14 and the rear evaporator form a refrigeration cycle where refrigerantcirculates through one compressor 11 and one condenser 12.

FIG. 1 is a view illustrating a state where a dual air conditioner for avehicle according to a prior art is installed in a car, FIG. 2 is aconfigurative view of the dual air conditioner for The vehicle accordingto the prior art, and FIG. 3 is a perspective view showing a part whererefrigerant is branched from the front air conditioner to the rear airconditioner in the dual air conditioner according to the prior art.

As shown in the drawings, the front air conditioner 10 includes: acompressor 11 for sucking and compressing refrigerant; a condenser 12for condensing refrigerant of high temperature and high pressure sentfrom the compressor 11; a front expansion valve 13 for throttling therefrigerant condensed and liquefied in the condenser 12; a frontevaporator 14 for evaporating the liquefied refrigerant of lowtemperature and low pressure throttled by the front expansion valve 13by heat-exchanging with air sent to the interior of the vehicle tothereby cool the air sent to the interior of the vehicle through theendothermic action by latent heat of vaporization of the refrigerant;and a pipe 16 for connecting the above-mentioned components with oneanother, so that the front air conditioner 10 can cool the front seat ofthe vehicle.

Moreover, the front air conditioner 10 further includes a dual pipe typeinternal heat exchanger 15, which has a dual pipe structure that isformed at a section of a front low-temperature pipe 16 a for connectingthe front evaporator 14 and the compressor 11 with each other and fronthigh-temperature pipes 16 b and 16 c for connecting the condenser 12 andthe front expansion valve 13 with each other, so as to heat-exchangerefrigerants flowing in the pipes with each other.

Here, the dual pipe type internal heat exchanger 15 heat-exchanges theliquid refrigerant of high-temperature and high-pressure, which is inthe state before it is throttled by the front expansion valve 13, withthe refrigerant gas of low-temperature and low-pressure discharged fromthe front evaporator 14, so that the refrigerant introduced into thefront evaporator 14 can move smoothly, a pressure drop of therefrigerant in the front evaporator 14 can be decreased, and an overheatregion (not shown) of the front evaporator 14, which has a relativelyhigher temperature, can be reduced because the dual pipe type internalheat exchanger 15 is set to completely evaporate the refrigerant inorder to prevent liquid refrigerant from being introduced into thecompressor.

Accordingly, the front air conditioner can stabilize the flow ofrefrigerant inside cooling tubes of the front evaporator 14 becausespecific volume of the refrigerant introduced into the front evaporator14 is reduced and the pressure drop of the refrigerant in the frontevaporator 14 is also reduced, and reduce the overheat region of thefront evaporator 14, which may cause a degradation of coolingperformance of the air conditioner due to the relatively highertemperature since the refrigerant introduced into the compressor 11 maybe overheated after being discharged from the front evaporator 14,whereby the cooling efficiency of the air conditioner can be improvedgreatly. Finally, the dual air conditioner can promote efficiencies ofthe compressor 11, the condenser 12, and the front evaporator 14 tothereby cause high efficiency and miniaturization of the airconditioner.

Moreover, the rear air conditioner 20 includes: a rear high-temperaturepipe 23 for branching refrigerant flowing from the condenser 12 of thefront air conditioner 10 toward the front expansion valve 13 to and arear expansion valve 21 for throttling the branched refrigerant; and arear evaporator 22 for evaporating refrigerant introduced from the rearexpansion valve 21 and joining the refrigerant with refrigerant flowingfrom the front evaporator 14 to the compressor 11, and cools the rearseat of the vehicle.

As described above, the front air conditioner 10 having the frontexpansion valve 13 and the front evaporator 14 and the rear airconditioner 20 having the rear expansion valve and the rear evaporator22 forms a refrigeration cycle commonly using one compressor 11 and onecondenser 12.

Hereinafter, a refrigerant circulation process of the dual airconditioner will be described.

First, when a cooling switch (not shown) is turned on, the compressor 11is driven by a driving force of an engine to suck and compressrefrigerant of low-temperature and low-pressure and to send refrigerantgas of high-temperature and high-pressure to the condenser 12, and then,the condenser 12 heat-exchanges the refrigerant gas with the outside airand condenses the refrigerant gas into a liquid of high-temperature andhigh-pressure. Next, the liquid refrigerant of high-temperature andhigh-pressure sent from the condenser 12 passes through an outer pipe 15b of the dual pipe type internal heat exchanger 15.

Continuously, some of the refrigerant passing through the outer pipe 15b of the dual pipe type internal heat exchanger 15 is introduced andexpanded into the front expansion valve 13 through the fronthigh-temperature pipe 16 c, and is introduced into the front evaporator14, and then, is evaporated by heat-exchange with air blown to the frontseat of the interior of the vehicle. The remainder of the refrigerant isintroduced and expanded into the rear expansion valve 21 through therear high-temperature pipe 23 branched from the front high-temperaturepipe 16 c, and is introduced into the rear evaporator 22, and then, isevaporated by heat-exchange with air blown to the rear seat of theinterior of the vehicle.

Through the above process, the front seat and the rear seat inside thevehicle are cooled. That is, the air blown by a blower (not shown) iscooled by latent heat of the refrigerant circulating in the evaporators14 and 22 while passing through the evaporators 14 and 22, and then, isdischarged to the interior of the vehicle in a cooled state.

Next, the refrigerant gas of low-temperature and low-pressure evaporatedand discharged from the front evaporator 14 and the refrigerant gas oflow-temperature and low-pressure evaporated and discharged from the rearevaporator 22 are joined together, and then, passes through the innerpipe 15 a of the dual pipe type internal heat exchanger 15.

In this instance, the refrigerant gas of low-temperature andlow-pressure passing through the inner pipe 15 a of the dual pipe typeinternal heat exchanger 15 heat-exchanges with liquid refrigerant ofhigh-temperature and high-pressure passing through the outer pipe 15 bof the dual pipe type internal heat exchanger 15, and then, is suckedinto the compressor 11 and recirculated in the above refrigerationcycle.

Moreover, as shown in FIGS. 2 and 3, the rear air conditioner 20branches the refrigerant circulating in the front air conditioner 10 andcirculates the refrigerant to the rear expansion valve 21 and the rearevaporator 22. That is, because the rear high-temperature pipe 23 isbranched from the front high-temperature pipe 16 c, which connects theouter pipe 15 b of the dual pipe type internal heat exchanger 15 and thefront expansion valve 13 with each other, the refrigerant can becirculated to the rear expansion valve 21 and the rear evaporator 22.

In this instance, in order to connect the front high-temperature pipe 16c and the rear high-temperature pipe 23 with each other, as shown inFIGS. 4 and 5, a connector 30 is used, and the connector 30 ismanufactured by the following process.

FIG. 4 illustrates a state where the front high-temperature pipe 16 c isdivided and the divide front high-temperature pipes 16 c are welded toboth ends of the connector 30, and the rear high-temperature pipe 23 iswelded to the connector 30 in a perpendicular direction.

FIG. 5 illustrates a state where the front high-temperature pipe 16perforates the connector 30 and the rear high-temperature pipe 23 iswelded to the connector 30 in the perpendicular direction. In thisinstance, the front high-temperature pipe 16 c, which perforates theconnector 30, has a hole.

However, the dual air conditioner for the vehicle according to the priorart has a problem in that the number of components and the number ofmanufacturing processes are increased because the rear high-temperaturepipe 23 is connected to the front high-temperature pipe 16 c via theconnector 30 in order to branch the refrigerant, which circulates insidethe front air conditioner 10, and circulate the branched refrigerant tothe rear air conditioner 20.

Furthermore, in the case that a distance between the dual pipe typeinternal heat exchanger 15 and the front expansion valve 13 is short,piping work and piping route of the front high-temperature pipe 16 c andthe rear high-temperature pipe 23 become complicated, and hence, a flowof the refrigerant is instable.

Additionally, because the rear high-temperature pipe 23 is branched fromthe connector 30 in the perpendicular direction, the flow of therefrigerant is instable.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve theabove-mentioned problems occurring in the prior arts, and it is anobject of the present invention to provide a dual air conditioner for avehicle, which includes a rear high-temperature pipe that is connectedto a rear expansion valve of a rear air conditioner and installed insuch a way as to be directly branched from a dual pipe type internalheat exchanger of a front air conditioner, thereby reducing the numberof required components and simplifying the manufacturing process with noneed to use a connector for branching the rear high-temperature pipefrom the front air conditioner, and enhancing a refrigerant movement andreducing material expenses and working process by simplifying pipingwork and a piping route.

To accomplish the above object, according to the present invention,there is provided a dual air conditioner for a vehicle comprising: afront air conditioner including compressor for sucking and compressingrefrigerant; a condenser for condensing refrigerant compressed in thecompressor, a front expansion valve for throttling the refrigerantcondensed in the condenser, a front evaporator for evaporating therefrigerant introduced from the front expansion valve, and a dual pipetype internal heat exchanger having a dual pipe structure formed at asection of a front low-temperature pipe for connecting the frontevaporator and the compressor with each other and front high-temperaturepipes for connecting the condenser and the front expansion valve witheach other, the dual pipe type internal heat exchanger heat-exchangingthe refrigerants that flow in the pipes with each other, the front airconditioner cooling the front seat side of the vehicle; and a rear airconditioner including a rear high-temperature pipe for branchingrefrigerant flowing from the condenser toward the front expansion valveand a rear expansion valve for throttling the branched refrigerant, anda rear evaporator for evaporating refrigerant introduced from the rearexpansion valve and joining the refrigerant with refrigerant flowingfrom the front evaporator to the compressor, the rear high-temperaturepipe being connected to a side of the dual pipe type internal heatexchanger in such a way as to be directly branched from the internalheat exchanger and being connected with the rear expansion valve, therear air conditioner cooling the rear seat side of the vehicle.

According to the present invention, the dual air conditioner for thevehicle, which includes a rear high-temperature pipe that is connectedto a rear expansion valve of a rear air conditioner and installed insuch a way as to be directly branched from a dual pipe type internalheat exchanger of a front air conditioner, does not require theconnector branching the rear high-temperature pipe from the front airconditioner, can reduce the number of required components and simplifythe manufacturing process, and allow simple piping work regardless witha distance between the dual pipe type internal heat exchanger and thefront expansion valve.

Moreover, the dual air conditioner according to the present, inventioncan enhance a refrigerant movement and reduce material expenses andworking process by simplifying the piping route of the rearhigh-temperature pipe.

Furthermore, the dual air conditioner according to the present inventioncan minimize a pressure loss of the refrigerant and provide a smoothflow of the refrigerant when the refrigerant passing through the outerpipe is distributed to the rear high-temperature pipe because the rearhigh-temperature pipe is directly branched from the expanded pipe partof the outer pipe of the dual pipe type internal heat exchanger.

Additionally, the dual air conditioner according to the presentinvention can allow a smooth flow of the refrigerant to the pipe ofhigh-temperature and high-pressure because the pipe is mounted to theexpanded pipe part, which has a diameter larger than the dual pipe typeinternal heat exchanger and is less hindered in fluid movement by theinner pipe.

In addition, the dual air conditioner according to the present inventioncan easily control, a flow rate of the refrigerant distributed to thepipes by controlling inclination angles and diameters of the fronthigh-temperature pipe and the rear high-temperature pipe, which arerespectively connected to the expanded pipe part of the outer pipe in acircumferential direction or in a longitudinal direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be apparent from the following detailed description ofthe preferred embodiments of the invention in conjunction with theaccompanying drawings, in which:

FIG. 1 is a view illustrating a state where a dual air conditioner for avehicle according to a prior art is installed in a car;

FIG. 2 is a configurative view of the dual air conditioner for thevehicle according to the prior art;

FIG. 3 is a perspective view showing a part where refrigerant isbranched from a front air conditioner to a rear air conditioner in thedual air conditioner according to the prior art;

FIGS. 4 and 5 are perspective view illustrating a state where a fronthigh-temperature pipe and a rear high-temperature pipe are joined by aconnector in the dual air conditioner according to the prior art;

FIG. 6 is a configurative view of a dual air conditioner for a vehicleaccording to the present invention;

FIG. 7 is a perspective view showing a part where refrigerant isbranched from a front air conditioner to a rear air conditioner in thedual air conditioner according to preferred embodiment of the presentinvention;

FIG. 8 is a sectional view taken along the line of A-A of FIG. 7;

FIG. 9 is a sectional view illustrating a dual pipe type internal heatexchanger of FIG. 6;

FIG. 10 is a partially sectional view showing a flow direction ofrefrigerant in the dual pipe type internal heat exchanger of FIG. 9;

FIG. 11 is a perspective view showing a part where refrigerant isbranched from the front air conditioner to the rear air conditioner inthe dual air conditioner according to another preferred embodiment ofthe present invention;

FIG. 12 is a sectional view illustrating a dual pipe type internal heatexchanger of FIG. 11;

FIG. 13 is an enlarged sectional view showing an expanded pipe part ofFIG. 12; and

FIG. 14 is an enlarged sectional view showing the expanded pipe part ofFIG. 13 according to another preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will be now made in detail to the preferred embodiment of thepresent invention with reference to the attached drawings.

A dual air conditioner 100 for a vehicle according to the presentinvention includes a front air conditioner 200 mounted in an engine roomof the vehicle and a rear air conditioner 300 mounted in the rear sideof the vehicle and branching refrigerant circulating in the front airconditioner 200.

First, the front air conditioner 200 has a refrigeration cycle includinga compressor 210, a condenser 220, a dual pipe type internal heatexchanger 250, a front expansion valve 230, and a front evaporator 240,which are connected with one another in order via a pipe P.

The compressor 210 is operated by receiving driving power from a powersupply (an engine, a motor, or others) to thereby inhale and compressrefrigerant of low-temperature and low-pressure in a gas phasedischarged from the front evaporator 240 and discharge the refrigerantin the gas phase of high-temperature and high-pressure to the condenser220.

The condenser 220 heat-exchanges the gas refrigerant of high-temperatureand high-pressure discharged from the compressor 210 with the outsideair, condenses it into a liquid phase of high-temperature andhigh-pressure, and then, discharges the condensed refrigerant to thefront expansion valve 230.

The front expansion valve 230 rapidly expands the liquid refrigerant ofhigh-temperature and high-pressure discharged from the condenser 220through the throttling action in such a way that the refrigerant ofhigh-temperature and high-pressure is turned into a saturated vaporphase of low-temperature and low-pressure, and then, sends therefrigerant to the front evaporator 240.

The front evaporator 240 heat-exchanges the liquid refrigerant oflow-pressure throttled in the front expansion valve 230 with air sent tothe interior of the vehicle, so that the refrigerant is evaporated,thereby cooling the air discharged to the interior of the vehicle due tothe heat absorption effect by latent heat of the refrigerant.

Continuously, the refrigerant gas of low-temperature and low-pressureevaporated from the front evaporator 240 is sucked into the compressor210, and is recirculated in the above cycle.

Furthermore, in the above refrigerant circulation process, cooling ofthe interior of the vehicle is achieved in such a way that the air blownby a blower (not shown) of the air conditioner for the vehicle is cooledby the evaporated latent heat of the liquid refrigerant circulating inthe evaporator 240 while passing through the front evaporator 240 anddischarged to the interior of the vehicle in a cooled state.

The dual pipe type internal heat exchanger 250 includes a dual pipestructure that is formed at a section of a front low-temperature pipe P3for connecting the front evaporator 240 and the compressor 210 with eachother and a high-temperature pipe P1 and a front high-temperature pipeP2 for connecting the condenser 220 and the front expansion valve 230with each other, so as to heat-exchange refrigerants flowing in thepipes with each other.

The dual pipe type internal heat exchanger 250 includes: an inner pipe251 disposed at the section of the front low-temperature pipe P3 forconnecting the front evaporator 240 and the compressor 210 with eachother; and an outer pipe 252 joined to the outer circumferential surfaceof the inner pipe 251 in a dual pipe structure.

In other words, as shown in FIGS. 9 and 10, the dual pipe type internalheat exchanger 250 includes: a spiral projection portion 251 a and aspiral groove portion 251 b formed on one of the inner pipe 251 and theouter pipe 252; a first refrigerant channel R1 formed inside the innerpipe 251; and a second refrigerant channel R2 formed between the innerpipe 251 and the outer pipe 252.

Here, the first refrigerant channel R1 is a channel that refrigerant (ofa gas phase) discharged from the front evaporator 240 and the rearevaporator 320 is joined and flows, and the second refrigerant channelR2 is a channel that refrigerant (of a liquid phase) discharged from thecondenser 220 flows.

Referring to FIGS. 9 and 10, the spiral projection portion 251 a and thespiral groove portion 251 b are formed on the outer circumferentialsurface of the inner pipe 251, and the outer pipe 252 that is a roundpipe is joined to the inner pipe 251 in the dual pipe structure.

In this instance, the spiral projection portion 251 a of the inner pipe251 is in close contact with the inner circumferential surface of theouter pipe 252, such that the second refrigerant channel R2 formedbetween the inner pipe 251 and the outer pipe 252 is formed in a spiralshape.

Moreover, both end portions the spiral projection portion 251 a and thespiral groove portion 251 b formed on the outer circumferential surfaceof the inner pipe 251 are ended inside an expanded pipe part 253 formedat both end portions of the outer pipe 252.

In the meantime, both ends of the outer pipe 252 are sealed by beingwelded with the outer circumferential surface of the frontlow-temperature pipe P3.

Furthermore, the outer pipe 252 has expanded pipe parts 253 formed atboth end portions thereof, wherein one of the expanded pipe part 253 iswelded and joined with the high-temperature pipe P1 that is connectedwith the condenser 220, and the other expanded pipe part 253 is weldedand joined with the front high-temperature pipe P2 that is connectedwith the front expansion valve 230.

As described above, because the outer pipe 252 has the expanded pipeparts 253 formed at both end portions thereof to enlarge the refrigerantchannel (flow channel sectional area), it can minimize a pressure lossof the refrigerant when the refrigerant is introduced into the outerpipe 252 or when the refrigerant is discharged from the outer pipe 252.

Additionally, the rear air conditioner 300 includes: a rearhigh-temperature pipe P4 for branching refrigerant of high-temperatureand high-pressure heading forward the front expansion valve 230 and arear expansion valve 310 for throttling the branched refrigerant; and arear evaporator 320 for evaporating refrigerant of low-pressure andlow-temperature introduced from the rear expansion valve 310 and joiningthe refrigerant to refrigerant flowing from the front evaporator 240 tothe compressor 210 and cools the rear seat of the vehicle.

In other words, the rear air conditioner 300 branches the refrigerantthrough the rear high-temperature pipe P4 before the refrigerant isintroduced into the front expansion valve 230 of the front airconditioner 200, and then, circulates the branched refrigerant to therear expansion valve 310 and the rear evaporator 320.

Moreover, the rear low-temperature pipe P5 connected to an outlet of therear evaporator 320 is connected with the front low-temperature pipe P3before it passes the dual pipe type internal heat exchanger 250 from thefront evaporator 240, so that the refrigerant, which is evaporated inthe rear evaporator 320, is evaporated in the front evaporator 240, andthen, joined with the refrigerant flowing in the front low-temperaturepipe P3.

Furthermore, the rear high-temperature pipe P4 is connected to a side ofthe dual pipe type internal heat exchanger 250 in such a way as to bedirectly branched, and then, is connected with the rear expansion valve310.

Accordingly, while the refrigerant discharged from the condenser 220 ofthe front air conditioner 200 flows to the front expansion valve 230through the outer pipe 252 of the dual pipe type internal heat exchanger250, some of the refrigerant flowing in the outer pipe 252 is directlybranched to the rear high-temperature pipe P4, and hence, flows to therear expansion valve 310.

Additionally, the rear high-temperature pipe P4 is welded and connectedto the expanded pipe part 253 of the outer pipe 252 connected with thefront high-temperature pipe P2, which is connected with the frontexpansion valve 230. That is, because the rear high-temperature pipe P4is connected to the expanded pipe part 253 of the outer pipe 252, it canminimize a pressure loss of the refrigerant and provide a smooth flow ofthe refrigerant when the refrigerant passing through the secondrefrigerant channel R2 of the outer pipe 252 is distributed to the rearhigh-temperature pipe P4.

In addition, a flow rate of the refrigerant distributed through thefront high-temperature pipe P2 and the rear high-temperature pipe P4,which are respectively connected to the expanded pipe part 253 of theouter pipe 252, can be controlled in various ways through the followingembodiments.

In a first preferred embodiment, as shown in FIG. 8, the fronthigh-temperature pipe P2 and the rear high-temperature pipe P4, whichare respectively connected to the expanded pipe part 253 of the outerpipe 252, are connected in a circumferential direction of the expandedpipe part 253 in a state where they are spaced apart from each other ata predetermined interval.

In this instance, the front high-temperature pipe P2 is connected to oneside (left side) relative to a vertical centerline C of the expandedpipe part 253 in such a way as to be inclined at a predetermined angle(θ1) in a downward direction (gravitational direction) and the rearhigh-temperature pipe P4 is connected to the other side (right side)relative to the vertical centerline C in such a way as to be inclined ata predetermined angle (θ2) in the downward direction (gravitationaldirection).

Here, it is preferable that the inclination angle (θ1) of the fronthigh-temperature pipe P2 relative to the vertical centerline C of theexpanded pipe part 253 is smaller than the inclination angle (θ2) of therear high-temperature pipe P4.

That is, because the front high-temperature pipe P2 connected to theexpanded pipe part 253 is inclined at the angle, which is closer toverticality than the rear high-temperature pipe P4, it is more affectedby the gravity force, and hence, relatively snore refrigerant introducedinto the expanded pipe part 253 after passing through the secondrefrigerant channel P2 of the outer pipe 252 is distributed to the fronthigh-temperature pipe P2 by the gravity force.

As described above, the inclination angles of the front high-temperaturepipe P2 and the rear high-temperature pipe P4, which are respectivelyconnected to the expanded pipe part 253 of the outer pipe 252, arecontrolled so that the flow rate of the refrigerant distributed to thepipes P2 and P4 can be controlled.

In a second preferred embodiment of the present invention, as shown inFIGS. 11 to 13, the front high-temperature pipe P2 and the rearhigh-temperature pipe P4, which are respectively connected to theexpanded pipe part 253 of the outer pipe 252, are spaced apart from eachother at a predetermined interval in a longitudinal direction of theexpanded pipe part 253.

In this instance, the front high-temperature pipe P2 and the rearhigh-temperature pipe P4 are connected at right angles to the downwarddirection (gravitational direction) of the expanded pipe part 253.

Moreover, in the second embodiment illustrated in FIGS. 11 to 13,because the front high-temperature pipe P2 and the rear high-temperaturepipe P4 are all connected at right angles to the downward direction ofthe expanded pipe part 253, diameters D1 and D2 of the fronthigh-temperature pipe P2 and the rear high-temperature pipe P4 arecontrolled so that the flow rate of the refrigerant distributed to thepipes P2 and P4 can be controlled.

Here, it is preferable that the diameter D1 of the fronthigh-temperature pipe P2 is larger than the diameter D2 of the rearhigh-temperature pipe P4 so that more refrigerant can be supplied to thefront evaporator 240, which is relatively larger than the rearevaporator.

Furthermore, because the front high-temperature pipe P2 and the rearhigh-temperature pipe P4 are spaced apart from each other at apredetermined interval in the longitudinal direction of the expandedpipe part 253, it is preferable that a length L2 of the expanded pipepart 253, to which the front high-temperature pipe P2 and the rearhigh-temperature pipe P4 are connected, is greater than a length L1 ofthe expanded pipe part 253, to which the high-temperature pipe P1 isconnected.

In a third preferred embodiment of the present invention, as shown inFIG. 14, the front high-temperature pipe P2 and the rearhigh-temperature pipe P4, which are respectively connected to theexpanded pipe part 253 of the outer pipe 252, are connected in arefrigerant flow direction of the expanded pipe part 253 in such a wayas to be spaced apart from each other at a predetermined interval.

In this instance, the front high-temperature pipe P2 and the rearhigh-temperature pipe P4 are respectively connected at right angles tothe downward direction (gravitational direction) of the expanded pipepart 253 and have the same diameter.

Additionally, in the third preferred embodiment illustrated in FIG. 14,because the front high-temperature pipe P2 and the rear high-temperaturepipe P4 are all connected at right angles to the expanded pipe part 253and have the same diameter, an arrangement order of the fronthigh-temperature pipe P2 and the rear high-temperature pipe P4, whichare respectively connected in the refrigerant flow direction of theexpanded pipe part 253, is changed so that the flow rate of therefrigerant distributed to the pipes P2 and P4 can be controlled.

Here, it is preferable that the front high-temperature pipe P2 isconnected closer to the upstream side of the refrigerant flow directionof the expanded pipe part 253 than the rear high-temperature pipe P4 sothat more refrigerant can be supplied to the front evaporator 240, whichis relatively larger than the rear evaporator.

That is, relatively more the refrigerant introduced into the expandedpipe part 253 after passing through the second refrigerant channel R2 ofthe outer pipe 252 is distributed to the front high-temperature pipe P2,which is arranged to the upstream side of the refrigerant flowdirection.

As described above, even though the diameters of the fronthigh-temperature pipe P2 and the rear high-temperature pipe 24, whichare respectively connected to the expanded pipe part 253 of the outerpipe 252 at right angles, are the same, the flow rate of the refrigerantdistributed to the pipes P2 and P4 can be controlled according to thearrangement order of the pipes P2 and P4.

In the meantime, because the front high-temperature pipe P2 and the rearhigh-temperature pipe P4 are connected in the refrigerant flow directionof the expanded pipe part 253 in such a way as to be spaced apart fromeach other at the predetermined interval, it is preferable that thelength L2 of the expanded pipe part 253, to which the fronthigh-temperature pipe P2 and the rear high-temperature pipe P4 areconnected, is greater than the length L1 of the expanded pipe part 253,to which the high-temperature pipe P1 is connected.

As described above, because the rear high-temperature pipe P4 isdirected connected to the expanded pipe part 253 of the outer pipe 252of the dual pipe type internal heat exchanger 250, the present inventiondoes not need the connector 30, which is required for branching the rearhigh-temperature pipe, and it causes reduction of the number of requiredcomponents and simplification in the manufacturing process, and allow aneasy and simple piping work regardless with a distance between the dualpipe type internal heat exchanger and the front expansion valve 230.

Moreover, a route of the rear high-temperature pipe P4 is simplified, sothat it can provide a smooth flow of refrigerant and cause reduction ofmanufacturing costs and working process.

Hereinafter, actions of the dual air conditioner 100 for the vehicleaccording to the present invention will be described.

First, the refrigerant gas of high-temperature and high-pressure, whichis compressed in the compressor 210, is introduced into the condenser220. The refrigerant gas introduced into the condenser 220 is condensedthrough heat-exchange with the outside air and phase-changed into liquidrefrigerant of high-temperature and high-pressure, and then, introducedinto one of the expanded pipe parts 253 of the outer pipe 252 of thedual pipe type internal heat exchanger 250.

The refrigerant of high-temperature and high-pressure introduced intothe expanded pipe part 253 of the outer pipe 252 is discharged from thefront evaporator 240 and the rear evaporator 320 while flowing in thesecond refrigerant channel R2 of the outer pipe 252, performsheat-exchange with the refrigerant of low-temperature and low-pressureflowing in the first refrigerant channel R1 of the inner pipe 251, andthen, is distributed to the front high-temperature pipe P2 and the rearhigh-temperature pipe P4, which are respectively connected to the otherexpanded pipe part 253.

Here, after the refrigerant distributed to the front high-temperaturepipe P2 is introduced into the front expansion valve 230, therefrigerant becomes in an atomized state of low-temperature andlow-pressure through decompression expansion, and then, is introducedinto the front evaporator 240. The refrigerant introduced into the frontevaporator 240 is evaporated by heat-exchange with the air blown to thefront seat of the vehicle, and at the same time, cools the air blown tothe front seat of the vehicle due to the heat absorption effect bylatent heat of the refrigerant.

Moreover, after the refrigerant distributed to the rear high-temperaturepipe P4 is introduced into the rear expansion valve 310, therefrigerant, becomes in an atomized state of low-temperature andlow-pressure through decompression expansion, and then, is introducedinto the rear evaporator 320. The refrigerant introduced into the rearevaporator 320 is evaporated by heat-exchange with the air blown to therear seat of the vehicle, and at the same time, cools the air blown tothe rear seat of the vehicle due to the heat absorption effect by latentheat of the refrigerant.

Continuously, the refrigerant gas of low-temperature and low-pressuredischarged from the front evaporator 240 after evaporation and therefrigerant gas of low-temperature and low-pressure discharged from therear evaporator 320 after evaporation are joined together through thefront low-temperature pipe P3 and the rear low-temperature pipe P5, andthen, passes the first refrigerant channel R1 of the inner pipe 251 ofthe dual pipe type internal heat exchanger 250.

In this instance, the refrigerant gas or low-temperature andlow-pressure passing through the first refrigerant channel R1 of theinner pipe 251 of the dual pipe type internal heat exchanger 250heat-exchanges with the refrigerant gas of high-temperature andhigh-pressure passing through the second refrigerant channel R2 of theouter pipe 252, and then, is recirculated in the above-mentionedrefrigeration cycle.

While the present invention has been described with reference to theparticular illustrative embodiments, it is not to be restricted by theembodiments but only by the appended claims. It is to be appreciatedthat those skilled in the art can change or modify the embodimentswithout departing from the scope and spirit of the present invention.

1. A dual air conditioner for a vehicle comprising: a front airconditioner including: a compressor for sucking and compressingrefrigerant; a condenser for condensing refrigerant compressed in thecompressor; a front expansion valve for throttling the refrigerantcondensed in the condenser; a front evaporator for evaporating therefrigerant introduced from the front expansion valve; and a dual pipetype internal heat exchanger having a dual pipe structure formed at asection of a front low-temperature pipe for connecting the frontevaporator and the compressor with each other and a high-temperaturepipe and a front high-temperature pipe for connecting the condenser andthe front expansion valve with each other, the dual pipe type internalheat exchanger heat-exchanging the refrigerants that flow in the pipeswith each other, the front air conditioner cooling the front seat sideof the vehicle; and a rear air conditioner including: a rearhigh-temperature pipe for branching refrigerant flowing from thecondenser toward the front expansion valve and a rear expansion valvefor throttling the branched refrigerant; and a rear evaporator forevaporating refrigerant introduced from the rear expansion valve andjoining the refrigerant with refrigerant flowing from the frontevaporator to the compressor, the rear high-temperature pipe beingconnected to a side of the dual pipe type internal heat exchanger insuch a way as to be directly branched from the internal heat exchangerand being connected with the rear expansion valve, the rear airconditioner cooling the rear seat side of the vehicle.
 2. The dual airconditioner according to claim 1, wherein the dual pipe type internalheat exchanger comprises: an inner pipe disposed at the section of thefront low-temperature pipe for connecting the front evaporator and thecompressor with each other; and an outer pipe joined to the outercircumferential surface of the inner pipe in a dual pipe structure, theouter pipe having expanded pipe parts formed at both ends thereof, oneof the expanded pipe parts being connected with the high-temperaturepipe connected with the condenser, the other of the expanded pipe partsbeing connected with the front high-temperature pipe connected with thefront expansion valve, and wherein the rear high-temperature pipe isconnected to the expanded pipe part of the outer pipe, to which thefront high-temperature pipe connected with the front expansion valve isconnected.
 3. The dual air conditioner according to claim 2, wherein thefront high-temperature pipe and the rear high-temperature pipe, whichare respectively connected to the expanded pipe part of the outer pipe,are connected in a circumferential direction of the expanded pipe partin a state where they are spaced apart from each other at apredetermined interval.
 4. The dual air conditioner according to claim3, wherein the front high-temperature pipe is connected to one side of avertical centerline of the expanded pipe part in such a way as to beinclined at a predetermined angle and the rear high-temperature pipe isconnected to the other side of the vertical centerline in such a way asto be inclined at a predetermined angle, and the inclination angles ofthe pipes are controlled so that a flow rate of the refrigerantdistributed to the pipes can be controlled.
 5. The dual air conditioneraccording to claim 4, wherein the inclination angle of the fronthigh-temperature pipe is smaller than the inclination angle of the rearhigh-temperature pipe.
 6. The dual air conditioner according to claim 2,wherein the front high-temperature pipe and the rear high-temperaturepipe, which are respectively connected to the expanded pipe part of theouter pipe, are connected in a longitudinal direction of the expandedpipe part in a state where they are spaced apart from each other at apredetermined interval, and diameters of the pipes are controlled sothat the flow rate of the refrigerant distributed to the pipes can becontrolled.
 7. The dual air conditioner according to claim 6, whereinthe diameter of the front high-temperature pipe is greater than thediameter of the rear high-temperature pipe.
 8. The dual air conditioneraccording to claim 6, wherein a length of the expanded pipe part, towhich the front high-temperature pipe and the rear high-temperature pipeare connected, is greater than a length of the expanded pipe part, towhich the high-temperature pipe is connected.
 9. The dual airconditioner according to claim 2, wherein the front high-temperaturepipe and the rear high-temperature pipe, which are respectivelyconnected to the expanded pipe part of the outer pipe, are connected ina refrigerant flow direction of the expanded pipe part in such a way asto be spaced apart from each other at a predetermined interval, and anarrangement order of the pipes, which are respectively connected in therefrigerant flow direction of the expanded pipe part, is changed so thatthe flow rate of the refrigerant distributed to the pipes can becontrolled.
 10. The dual air conditioner according to claim 9, whereinthe front high-temperature pipe is connected closer to the upstream sideof the refrigerant flow direction of the expanded pipe part than therear high-temperature pipe.
 11. The dual air conditioner according toclaim 9, wherein the dual pipe type internal heat exchanger comprises aspiral projection portion and a spiral groove portion formed on one ofthe inner pipe and the outer pipe; a first refrigerant channel formedinside the inner pipe; and a second refrigerant channel formed betweenthe inner pipe and the outer pipe.
 12. The dual air conditioneraccording to claim 11, wherein the first refrigerant channel is achannel that the refrigerant discharged from the front evaporator andthe rear evaporator is joined and flows, and the second refrigerantchannel is a channel that the refrigerant discharged from the condenserflows.